In modern control systems for internal combustion engines, measuring devices are often used for detecting operating variables of the internal combustion engine or of the motor vehicle. The measuring signals of the measuring devices define the basis for the control of the engine. Unwanted operating conditions of the engine are a result of malfunctions in the area of the measuring devices. For this reason, these measuring devices must be monitored as to their operability. Such a monitoring has special significance for electronic engine power control systems (electronic accelerator-pedal systems) wherein the power of the engine and therefore the speed of the motor vehicle is controlled. This control is achieved on the basis of measuring signals from position transducers for a driver-controlled element and, if required, for a power positioning element. Therefore, in the past, various measures for monitoring such a position transducer have been suggested. For example, it is known from U.S. Pat. No. 5,320,076, to provide three position transducers in combination with a power positioning element with the measuring signals of the position transducers being checked with respect to each other as to plausibility and, in the event of a fault, one of the measuring devices controls the internal combustion engine on the basis of the two measuring devices which remain operational in the sense of a two-out-of-three selection. Such a procedure could, however, hardly be satisfactory in several embodiments when viewed in the context of its complexity.